1. Field of the Invention
The present invention relates to a fluid-pressure shock absorber, and more particularly to a fluid-pressure shock absorber provided with a bump cap.
2. Description of the Related Art
In a fluid-pressure shock absorber which is applied to a suspension device of a vehicle, there is, for example, a fluid-pressure shock absorber, where a bump cap is arranged at an open portion of an external cylinder thereof. (refer to, for example, Japanese Patent Application Laid-open No. 2007-57088). With a fluid-pressure shock absorber where a coil spring is coaxially arranged and an internal diameter of the coil spring is close to an external diameter D0 of an external cylinder, an external diameter D1 of the bump cap is limited to the external diameter D0 of the external cylinder or less (D0≦D1). Here, in a certain fluid-pressure shock absorber, a small-diameter portion of an external diameter D2 (D0≧D1>D2) is formed at the open portion of the external cylinder, and the bump cap, its external diameter D1 of which is equal to or less than the external diameter D0 of the external cylinder, is pressed into the small-diameter portion. However, as regards a fluid-pressure shock absorber where its open portion of an external cylinder is closed by means of caulking treatments such as curling processes, some difficulties can be found when a small-diameter portion is formed at the open portion of the external cylinder. Moreover, in some cases it becomes impracticable to install certain parts such as a piston inside the absorber due to formation of the small-diameter portion. Accordingly, in the fluid-pressure shock absorber where the open portion of the external cylinder thereof is closed by means of the caulking treatments, there is a need for a structure for retaining a bump cap with an external diameter D1 not overly exceeding the external diameter D0 of the external cylinder.